Heat Flashcards
What is the normal human temperature
37°C
What is thermoregulation
The process that allows the body to maintain core temperature
What do thermometers do
Detect change in temperature to cause vasodilation of arterioles then increase blood flow to the skin
How is heat lost
Evaporation (sweating) and convection
What does sweating lead to
Fluid loss, heat loss
How much water can be lost from athletes in hot conditions
Up to 3L per hour
What mainly affects performance when in hot conditions
Dehydration
What is muscle power output
1% drop in body weight, can cause a 10-15% reduction performance
What is the amount of sweat affected by
Humidity (% of water in the air)
Define cardiovascular drift
Cardiovascular Drift is the potential side effect of exercise in a hot climate
What does cardiovascular drift lead to
Increased hr during sub maximal exercise
What does a 1°C rise in temperature lead to
Upward drift of HR by 10bpm
What does the cardiovascular drift lead to
Redirection of blood flow to skin reduces blood flow to muscle and venous return.
Fluid loss and therefore blood plasma through sweating results in increased blood viscosity (thickness).
SV decreases so HR increases to maintain Q
What is the impact of heat on the body’s thermoregulatory response
Dilation of arterioles/ capillaries to skin to increase blood flow in limbs.
Decreased blood plasma volume.
Increased HR, reduced oxygen to working muscles, earlier fatigue due to venous return, Q, SV and blood pressure
Dehydration
Drying of airways leads to increased mucus production, constriction of airways and decreased volume of gas exchange
Increase breathing rate leads to increased oxygen cost of exercise and reduced aerobic energy production
High levels of sunlight causes pollutants (e.g. dust) which can irritate airways
What are the overall physiological impacts of heat
Aerobic performance decreases
Fatigue sets in faster
Strength endurance is reduced
Dehydration
